Methanation reaction or the conversion of carbon monoxide (CO) and carbon dioxide (CO2) to methane (CH4) through hydrogenation is long-established method, but recently, attention has been paid to methanation reactions as a practical method for carbon dioxide reduction and a tool for renewable energy storage. One of important component for higher outcomes of product is selection of a catalyst that corresponds to methanation reaction boundaries. This paper focuses of definition of methanation reaction boundaries and characteristics of different catalysts properties that have been investigated in recent studies worldwide. Based on the review of researches, a basic classification of catalysts is proposed.